What's your problem? Both sources state that the number of transistors will double approximately every two years. As Moore is a founder of Intel, why not trust Intel the most? Also, if you read the sources of wikipedia, you'll find that Moore himself adjusted his prediction.
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FalconSep 2 '11 at 16:58

The CEO of a company I once worked for said that More's law was that "Your profits should double every 18 months" and he was DEAD serious.
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aceintheholeSep 2 '11 at 19:34

+1 for a link to the article. Note that "optimal" was based on the manufacturing cost per component. There are fixed costs for running a wafer through a FAB, so the more components you can fit per wafer (unit area) the less expensive your per-component cost is. If you pack them too tightly, however, you increase the risk of creating defective units, which start driving your per-unit cost back up again.
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Jay ElstonSep 2 '11 at 17:24

Moore slightly altered the formulation of the law over time, in
retrospect bolstering the perceived accuracy of his law.[17] Most
notably, in 1975, Moore altered his projection to a doubling every two
years.[18] Despite popular misconception, he is adamant that he did
not predict a doubling "every 18 months". However, David House, an
Intel colleague, had factored in the increasing performance of
transistors to conclude that integrated circuits would double in
performance every 18 months.[note 1]

actually Moore's Law is not so much of a law as it is a target; each year, the CPU industry uses Moore's Law to calculate the density/cost that they will be aiming for their next fab plant that they will be building. The law is used to determine hiring strategy, R&D expenditure, etc so that the "Law" is fulfilled year by year.
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Lie RyanSep 2 '11 at 20:45